1. Field of the Invention
The invention is related to the field of communications, and in particular, to the conversion of optical wavelengths for optical signals.
2. Description of the Prior Art
Optical communication networks transfer optical signals over optical wavelengths. The optical signals typically employ amplitude modulation to carry user data. Sometimes, it may be desirable to convert the wavelength of an optical signal to a different wavelength. Unfortunately, the conversion of wavelengths in an optical signal has often required the inefficient conversion of the optical signal into the electrical format.
All-optical wavelength conversion refers to the fact the wavelength of the optical signal is converted without converting the optical signal itself into the electrical format. All-optical wavelength conversion for amplitude-modulated optical signals has been developed. However, optical signals will increasingly employ phase modulation to carry user data. At present, all-optical wavelength conversion for phase-modulated optical signals has not been developed to provide an effective solution. Thus, the inefficient conversion of the optical signal into the electrical format may still be required when performing wavelength conversion for a phase-modulated optical signal. A Mach-Zehnder interferometer can convert the modulation of an optical signal between phase modulation and amplitude modulation. Unfortunately, these components have not been effectively implemented to provide all-optical wavelength conversion for phase-modulated optical signals.